Load transmission device

ABSTRACT

The present invention relates to bars for load transmission, which if anchored in concrete slabs create a support between them, forming semi-rigid joints and accompanying the differential settlements of the foundation bed, as a result of the rotation in the vertical direction about the joint axis, and transmitting the load from a slab to the other, ensuring a perfect leveling of the surface thereof when occurring elastic movements of the foundations, and allowing the possibility of removing the slabs at any time and reuse them again, due to the telescopic effect of the bars. The telescopic function of the bar which allows its support between slabs created a new possibility of obtaining prefabricated floorings of easy manufacture and assembly in situ, creating a new concept in the construction of roads, ports, airports, railways, industrial areas, etc., which distinguishes the present invention from the closest state of the art.

FIELD OF THE INVENTION

The scope of the present invention is the construction and public works,namely construction with concrete and specifically construction of roadsand highways, ports, airports, railways and industrial areas.

TECHNICAL BACKGROUND OF THE INVENTION

The following patent documents were identified through a research on theprior art in the field of the invention:

(D1) The CN 1800540 A—D1 describes a hollow reinforced concrete slabcomprising hollow elements of reinforced concrete. The elements areconcreted “in situ” and reinforced with a concrete rib. The hollowelements comprise a formwork cavity. The invention can be applied tovarious solutions of molded and reinforced concrete, such as roofs ofbuildings, foundation slabs, walls and bridges;

(D2) CN 203401620 U—D2 is a utility model which discloses a connectorfor steel bars and is designed with the objective of solving theproblems associated with the reinforcing steel bars, which may includethe use of electrical and mechanical equipment, before or during theconstruction, to connect the reinforcing threaded steel bars used inconstruction. The invention comprises a casing tube, internal screwthreads, and fixing screws and is characterized in that the internalthreads are embedded in the inner wall of the casing tube; and in thatit includes a plurality of fixing screws arranged in the locationcorresponding to the internal screw threads;

(D3) CN 203008388 U—D3 discloses a steel support bar fixed in areinforced concrete slab casted “in situ”. It comprises a sleeve tube,an end cap, a support rod, a block, a locking bar, a nut and a lockinglatch, in which the lower part of the sleeve tube is toothed while thelower middle part of the sleeve tube is closed.

The present invention relates to telescopic bars for load transmissionanchored and cast in cement concrete slabs, which allow the transmissionof loads from a slab to the adjacent slabs, and not only ensure thetransmission of said loads but, simultaneously, also prevent thedifferential settlement of those slabs.

The telescopic function of the bar which allows its support betweenslabs created a new possibility of obtaining prefabricated flooringseasy to manufacture and assemble in situ, creating a new concept in theconstruction of roads, ports, airports, railways, industrial areas,etc., which distinguishes the present invention from the closest stateof the art.

Additionally, the possibility of obtaining concrete roads with thesetelescopic bars, and the fact that the constituent slabs can beprefabricated, remarkably reduces the environmental impact since theconstituent elements do not release pollutants, neither in themanufacture nor in the application and use.

Once the telescopic bars for load transmission are alternately arrangedand anchored in the base of the slabs along the backrest joints, thebending stresses in the upper edge of said slabs decrease and a rotationabout its axis in the vertical direction of said joints is allowed.

Thus, any unevenness in the upper joint edge formed by the separation ofthe slabs can be eliminable, whether these slabs are pre-molded or not.

Additionally to the above, it should be noted that if the foundationssuffer differential settlements due to its elastic function or byerosion of the same, these concrete slabs will be able to follow thesemovements, ensuring the leveling in the axis of the backrest joints, andallowing the slabs to rest entirety on the foundation, thus beingsubjected to compressive stresses and reducing the stresses generated bythe flexion/traction forces caused by the transmission of the loads.

As can be seen, these bars which allow prefabrication of concrete slabsfor ground floors over elastic foundations also allow a furtherpossibility consisting in obtaining over-elevations at the outer radiusof curves, which are so far impossible by techniques of in situconcreting due to the sag of the concrete thus creating shrinkage cracksand putting slabs out of use.

This possibility results from the manufacture of slabs in molds withpredefined curvature, thus maintaining a perfect planimetry even whenthe over-elevation bend of the curves is marked.

The use of telescopic bars, since they allow prefabrication of concreteslabs, also allow obtaining curves with constant radius aftertopographical information, increasing the safety and convenience of roadtraffic.

Thus, we can conclude that these two advantages of over-elevations ofthe outer radius of the curve and constant radius will save countlesslives in the future and increase the driving speed—thus increasingsavings in the transport of commodities, people and goods and increasingsavings in the fuel consumption.

The innovation of the invention consists in the ability of creating aflexible load transmission support, after the execution or placement ofprefabricated slabs of cement concrete, for building ground floors inhighways, roads, airports, ports and industrial areas.

This possibility of having telescopic bars which extend or are retractedunderneath contiguous slabs, not only allows to place the slabs as wellas to remove them whenever necessary (repair the foundations or placingtubes for underpasses, etc.), thus allowing obtaining removable slabs.

These removable slabs allow placement (mounting) through the use ofcranes over any land or deformable material (EPS type, etc.) in any kindof weather conditions (freezing, rain, sun, wind, day, night, etc.).

In summary, the telescopic bars object of the present invention allowthe pre molding of slabs with numerous technical and economic advantagescompared to the prior art, such as:

-   a) Speed of construction:

i. Placement of the pre molded slabs using a crane. Manpower of thisoperation=3 men;

ii. Placing in work shifts, since the slabs are already prefabricated,allowing a continuous placing without interruption;

iii. Placing with any atmospheric weather (rain, freezing anddefrosting, positive and negative temperatures, sun, fog, etc.);

iv. Immediate use;

v. Eliminating manpower and heavy equipment for in situ construction;

-   b) Economy

i. Absence of manpower to build in situ;

ii. No heavy equipment;

iii. Immediate use;

iv. Useful life span exceeding 50 years;

-   c) Foundations

i. Soil with low support, less than one kilogram/cm³

ii. Expansive soils

iii. Artificial soils EPS, stabilized soils (cement, lime, etc.)

-   d) Quality of the concrete

i. Concrete of high resistance and easy control in manufacturing;

ii. Concrete of high mechanical wear strength with optimizedprefabricated ribbing;

iii. Concrete manufactured and molded under optimum conditions oftemperature and humidity;

-   e) Levelling of slabs and planimetry: optimized to 0 mm;-   f) Applications:

i. Curves with high over-elevations with the required angle;

ii. Curves with constant radius;

iii. Large tilt angles (up and down);

iv. Coverage of embankments;

v. Ideal for construction of railways, roads and highways, either inurban or open fields, ports and airports and industrial areas, etc.;

-   g) Adherence and security controlled in project and in factory:    ribbing with optimized prefabrication;-   h) Environmental impact: The possibility of obtaining concrete roads    with these telescopic bars, and the fact that the constituents can    be prefabricated slabs, remarkably reduces the environmental impact    since the constituent elements do not release pollutants neither in    the manufacture, nor in the placement and use.

BRIEF DESCRIPTION OF THE DRAWINGS

The description that follows is based on the appended figures whichrepresent, without any limiting characteristic:

FIG. 1—A schematic perspective view of the telescopic bar object of theinvention in its essential embodiment, i.e. the first described below,in which the telescopic bar for load transmission (1) is representedwith a rack (male), which runs inside a sheath and an anchoring arc (3),with lower and upper alignment and strengthening armatures (10) and twoopenings with underpass of the slabs (11).

FIG. 2—A schematic perspective view of a second embodiment of theinvention in which the telescopic transmission bar (1) is represented,which runs inside a sheath (2) and an anchoring arc (3), with lower andupper alignment and strengthening armatures (10), a key for rotation (9)of the pinion, which will extend the telescopic bar (1), an accesschamber (6) to the pinion, two openings (11) with underpass of the slabsfor placement of lifting and mounting hooks, vertical ribs/guides foraligning the slabs at the assembly stage.

FIG. 3—An elevation view of the telescopic bar for load transmission ofa second embodiment of the invention, in which all the same componentsof FIG. 2 are shown, but with the pinion (5) being visible.

FIG. 4—A perspective view of the telescopic bar of a second embodimentof the invention, in which all the same components of FIG. 3 are shown,but with the rack (4) being visible.

DETAILED DESCRIPTION OF THE INVENTION

As can be seen in the figures, the bar for load transmission (1) isprovided with telescopic movement inside a sheath (2). This bar (1) isprovided with an anchoring arc or bar (3) which, as the name implies, isfixed to the slab represented as a dashed line.

The telescopic function of the transmission bars (1) is ensured by asystem which transforms the rotary motion of a part in a rectilinearmotion of another part. In this particular case, it is used a systemcomprising a rack and pinion or an endless screw and sector system. Inthe illustrated case, the pinion (5) at the end of a rotation key (9),actionable from the surface of the slab, moves the rack (4) in thesurface of the telescopic bar. The key (9) is inserted in an accesschamber (6). The pinion (5) inserted in a box can be adjusted through anadjusting nut (7) and locked by means of a locking pin (8). Thistransmission system allows moving the bar from back to front, being in asheath already pre anchored in the contiguous pre molded slab, therebycreating a semi-continuous support between said slabs.

The pinion (5) can be visited from the surface of the slab through anegative in the form of cylindrical tube, coincident with the nut of thegear (pinion) and with the safety pin, for introduction of a wrenchwhich will allow the displacement of said bar or, if rotated in theopposite direction, the retraction of the same.

This access will be filled with a material easily removable a posteriori(EPS, sponge, etc.) and properly sealed at the slab surface in order toprevent the passage of liquids and diverse dirt, which in the futurewould prevent the proper functioning of the pinion or which would damageit.

As can be understood from the previous description, the slab comprises achannel for insertion of the acceptance sheath (2) functioning as thefemale part of the transmission system, while the bar (1) functions asthe male part of the same system. These channels for the insertion ofthe sheaths (2) are drawn in the bottom of the slab. Said slab furthercomprises upper and lower alignment and strengthening armatures (10),vertical ribs/guides for alignment during assembly of the various slabs,and two openings (11) with underpass of the slabs for placing liftinghooks and mounting the same.

The acceptance sheaths (2) (female part) may be lined with a durablematerial (carbon fiber, etc.) and still eliminating any noise which mayresult from the contact of an iron bar against an iron sheath.

Once the telescopic bars for load transmission (1) are alternatelydisposed and anchored in the base of the slabs along the backrestjoints, the bending stresses in the upper edge of said slabs decreaseand a rotation about its axis in the vertical direction of said jointsis allowed.

Thus, any unevenness in the upper joint edge formed by the separation ofthe slabs can be eliminable, either these slabs are pre molded or not,as aforementioned. The shear stress in the telescopic bars will beverified in order to not introduce flexion/traction forces higher thanthe concrete slab resistance when it is subject to load.

PREFERRED WAYS OF CARRYING OUT THE INVENTION

In a first preferred embodiment of the invention, the fabrication of theslabs in bend molds is pre-defined, i.e. a perfect planimetry ismaintained even when the over-elevation bend of the curves is marked. Insummary, in a first embodiment the bar (1) is provided with an anchoringarc or bar (3) with fixed curvature.

In a second preferred embodiment of the invention, the telescopic barsfor load transmission (1) are constituted by a single piece which isanchored to the slab in the same position and alignment, and whichaccepts the acceptance sheaths of the adjoining slab, maintaining thesame type of function as the telescopic bar.

In a third preferred embodiment of the invention, the bars (1) mayrotate about an axis with a limited travel, in which a bar is alreadypre fixed in an acceptance slab and the extension of the same isinserted in a sheath which is screwed to a rigid base, anchored in theadjoining slab. This bar (1) is placed on top of the slab and allows theconstruction of slabs of variable length and width, ensuring the concaveand convex connections of constant radius between two planes withvariable angle. Thus, the concordances between ascent and descent,respectively for higher and lower planes, allows for the in situplacement of small segments of pre molded slabs, joined together bythese bars in the axis of the joints, avoiding the sophisticatedfabrication of molds with side diaphragm and bases of flexible material,only possible in sophisticated industrial facilities, thus solving withthe same efficacy the mentioned concordances between different planes.

In a fourth preferred embodiment of the invention, the bars (1) areexecuted in a similar way as the third embodiment, however they havelarger dimensions and are placed laterally along the thickness of theslab, where access to the top of the slab is difficult or does not allowthe filling of the attachment zone of the acceptance sheaths, due to theexcessive abrasion.

1. Telescopic bar for load transmission (1) anchored in concrete slabsthat create a support between them, forming semi-rigid joints,characterized in that it consists of a single piece which is cast andanchored to the slab and it comprises a transmission system from rotarymotion into rectilinear motion actionable from the surface of the slab,which system moves the bar (1) from back to front.
 2. Use of telescopicbars (1) as described in claim 1 in prefabricated concrete slabs,characterized in that said telescopic bars for load transmission areanchored or—casted in cement concrete slabs and execute the loadtransmission from a slab to the adjacent slabs.